Cesium and strontium extraction using a mixed extractant solvent including crown ether and calixarene extractants

Abstract

A mixed extractant solvent including calix[4]arene-bis-(tert-octylbenzo)-crown-6 (“BOBCalixC6”), 4′,4′,(5′)-di-(t-butyldicyclo-hexano)-18-crown-6 (“DtBu18C6”), and at least one modifier dissolved in a diluent. The mixed extractant solvent may be used to remove cesium and strontium from an acidic solution. The DtBu18C6 may be present from approximately 0.01 M to approximately 0.4M, such as from approximately 0.086 M to approximately 0.108 M. The modifier may be 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (“Cs-7SB”) and may be present from approximately 0.01M to approximately 0.8M. In one embodiment, the mixed extractant solvent includes approximately 0.15M DtBu18C6, approximately 0.007M BOBCalixC6, and approximately 0.75M Cs-7SB modifier dissolved in an isoparaffinic hydrocarbon diluent. The mixed extractant solvent may form an organic phase in an extraction system that also includes an aqueous phase. Methods of extracting cesium and strontium as well as strontium alone are also disclosed.

1. A method of separating cesium and strontium from an acidic solution, comprising:
 contacting an acidic solution comprising cesium and strontium with a mixed extractant solvent consisting of calix[4]arene-bis-(tert-octylbenzo)-crown-6 (“BOBCalixC6”), 4′,4′,(5′)-di-(t-butyldicyclo-hexano)-18-crown-6 (“DtBu 18C6”), and 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (“Cs-7SB”) dissolved in a diluent; and 
 removing the cesium and strontium from the acidic solution. 
 
     
     
       2. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed extractant solvent comprises providing the acidic solution comprising from approximately 0.5M to approximately 3M nitric acid. 
     
     
       3. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed solvent extractant comprises contacting the acidic solution with the mixed extractant solvent comprising from approximately 0.0025M to approximately 0.025M BOBCalixC6. 
     
     
       4. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed solvent extractant comprises contacting the acidic solution with the mixed extractant solvent comprising from approximately 0.01M to approximately 0.5M DtBu18C6. 
     
     
       5. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed solvent extractant comprises contacting the acidic solution with the mixed extractant solvent comprising from approximately 0.086 M to approximately 0.108 M DtBu18C6. 
     
     
       6. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed solvent extractant comprises contacting the acidic solution with the mixed extractant solvent comprising from approximately 0.2M to approximately 1.0M Cs-7SB. 
     
     
       7. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed solvent extractant comprises contacting the acidic solution with the mixed extractant solvent comprising a diluent that includes an isoparaffinic hydrocarbon. 
     
     
       8. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed solvent extractant comprises contacting the acidic solution with the mixed extractant solvent consisting of approximately 0.15M DtBu18C6, approximately 0.007M BOBCalixC6, and approximately 0.75M Cs-7SB modifier dissolved in an isoparaffinic hydrocarbon diluent. 
     
     
       9. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed extractant solvent comprises forming a first organic phase and a first aqueous phase. 
     
     
       10. The method of  claim 1 , wherein contacting an acidic solution comprising cesium and strontium with a mixed extractant solvent comprises extracting the cesium and strontium into a first organic phase. 
     
     
       11. The method of  claim 1 , wherein removing the cesium and strontium from the acidic solution comprises separating a first organic phase and a first aqueous phase. 
     
     
       12. The method of  claim 1 , wherein removing the cesium and strontium from the acidic solution comprises removing the cesium and strontium at a temperature ranging from approximately 1° C. to approximately 40° C. 
     
     
       13. The method of  claim 1 , wherein removing the cesium and strontium from the acidic solution comprises removing the cesium and strontium at a temperature ranging from approximately 10° C. to approximately 15° C. 
     
     
       14. The method of  claim 1 , further comprising recovering the mixed extractant solvent, the cesium, and the strontium. 
     
     
       15. The method of  claim 14 , wherein recovering the mixed extractant solvent, the cesium, and the strontium comprises contacting a first organic phase with a second aqueous phase. 
     
     
       16. The method of  claim 15 , wherein contacting a first organic phase with a second aqueous phase comprises extracting the cesium and strontium into the second aqueous phase. 
     
     
       17. The method of  claim 15 , wherein contacting a first organic phase with a second aqueous phase comprises contacting the first organic phase with the second aqueous phase at a temperature ranging from approximately 10° C. to approximately 60° C. 
     
     
       18. The method of  claim 15 , wherein contacting a first organic phase with a second aqueous phase comprises contacting the first organic phase with the second aqueous phase at a temperature ranging from approximately 20° C. to approximately 40° C. 
     
     
       19. The method of  claim 15 , wherein contacting a first organic phase with a second aqueous phase comprises contacting the first organic phase with an aqueous solution comprising from approximately 0.001M nitric acid to approximately 0.5M nitric acid. 
     
     
       20. The method of  claim 14 , wherein recovering the mixed extractant solvent, the cesium, and the strontium comprises separating a first organic phase and a second aqueous phase. 
     
     
       21. A method of extracting strontium, comprising:
 contacting an acidic solution comprising strontium with a solvent comprising 4′,4′,(5′)-di-(t-butyldicyclo-hexano)-18-crown-6 (“DtBu 18C6”), 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (“Cs-7SB”), and an isoparaffinic hydrocarbon.